Evaluation of release rates and control of biofouling using monolithic coatings containing an isothiazolone

A commercially available isothiazolone, Sea‐Nine 211 (c‐9211) has been used to study the controlled release characteristics and antifouling behavior of non‐ablative coatings based upon a vinyl chloride/vinyl acetate copolymer resin (VYHH). The governing release mechanism was found to be Fickian diffusion when c‐9211 is released from a monolithic coating over the course of 30 d. The extent of fouling was evaluated for a number of marine fouling species found at Taylor's Creek, Beaufort, North Carolina, and Pearl Harbor, Oahu, Hawaii, in relation to the rate of release of c‐9211 from the coating. The efficacy of c‐9211 as a single antifouling agent was determined based on the minimum flux required to keep the coating free of fouling, c‐9211 shows promise against a wide variety of fouling species in the marine environment above a flux of 5–7 μg.cm2.d‐1, with the exception of barnacles and to some extent, diatoms, which do not seem to be well controlled by c‐9211 at fluxes as high as 15 μg.cm2.d‐1.